05000263/LER-2001-001
| Docket Number | |
| Event date: | 01-10-2001 |
|---|---|
| Report date: | 03-23-2001 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i) |
| 2632001001R01 - NRC Website | |
FACILITY NAME(1) DOCKET LER NUMBER (6) PAGE (3)
MONTICELLO NUCLEAR YEAR SEQUENTIAL NUMBER REVISION NUMBER
Description On January 10, 2001, while following up on questions from the Monticello Senior NRC Resident Inspector, it was discovered that several instrument and control procedures did not specify the proper way to perform independent verification following the return to service of instrument channels being tested.
Reactor and plant protection system' instrument channels2 are tested and calibrated individually. Following confirmation of trip settings and proper operation of associated relays and annunciators, each channel is returned to service. An independent verification that the instrument channel was properly returned to operable status should be made prior to removing the next channel from service It was determined that several instrument and control procedures are deficient in the way in which the independent verification is performed. In several cases independent verification was not specified until the last step in the procedure following testing of all channels.
Event Analysis
Analysis of Reportability This Licensee Event Report is being submitted pursuant to the pre-January 23, 2001, version of 10 CFR 50.73(a)(2)(i). The deficient procedures did not require independent verification of each instrument channel prior to removing the next channel from service.
Therefore more than the allowed number of instrument channels and trip systems were considered inoperable and the condition violated the Monticello Technical Specifications, including Tables 3.1.1, 3.2.1, and 3.2.2.
1EIIS System Code: � JE 2Component Function Identifier: CHA FACILITY NAME(1) DOCKET LER NUMBER (6) PAGE (3)
MONTICELLO NUCLEAR YEAR SEQUENTIAL NUMBER REVISION NUMBER
Safety Significance
If an error was made in restoring an instrument channel to service, more than one channel could be disabled until independent verification was performed at the last step of the procedure. The probability of making an error was low because restoration was performed per a procedural step. Because the probability was low, and because the duration to complete the procedure was short, the safety significance of these procedural deficiencies was small and the health and safety of the public was not affected. The discovered procedural deficiencies represent, however, a failure to comply with the plant's licensing bases with respect to equipment operability determination.
Cause
The apparent cause of this event is an initial lack of understanding of the role of independent verification in demonstrating operability. Monticello is committed to perform independent verification of activities in accordance with Item I.C.6 of NUREG- 0737, "NUREG-0737, "Clarification of TMI Action Plan Requirements," October 31, 1980. When Monticello initiated the requirements for independent verification, actions were taken to upgrade all plant procedures, including instrument and control test and calibration procedures, to implement independent verification practices where required.
A determination was made at the time that completion of the independent verification steps was not required prior to considering a component operable. This determination has now been found to be incorrect.
On June 26, 1984, the NRC issued IE Information Notice 84-51, "Independent Verification." At this time all plant work groups were instructed to review their procedures and processes to ensure that independent verification activities were implemented where necessary. Also, at this time, plant administrative directives were revised to emphasize the importance of independent verification to ensure equipment operability. Due to the ambiguity of guidance contained in the plant administrative directives, instrument test and calibration procedures were considered at the time to be acceptable.
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MONTICELLO NUCLEAR YEAR SEQUENTIAL NUMBER REVISION NUMBER
The root causes of this event are being pursued under the Monticello corrective action program.
Corrective Action Following discovery of this deficiency, a hold was placed on affected Monticello Instrument and Control Group Technical Specification procedures. Procedures found to deficient will be revised prior to their next use.
Plant administrative directives will be clarified to emphasize the requirements of independent verification completion prior to considering the affected component operable.
Training will be provided to appropriate members of the plant staff following clarification of the administrative directives to assure full and complete understanding of the purpose and correct implementation of independent verification.
Other plant work groups have been informed of this deficiency in the independent verification process in instrument and control procedures and of plant management's expectation that independent verification will be properly conducted on return to service of safety related components.
A review of other categories of plant procedures will be conducted to verify compliance with the intent of plant directives regarding independent verification.
A case study of the event will be presented to affected supervisors. The study will focus on "cultural issues" and how these issues affect each supervisor's area.
Failed Component Identification Not applicable.
FACILITY NAME(1) DOCKET LER NUMBER (6) PAGE (3)
MONTICELLO NUCLEAR YEAR SEQUENTIAL NUMBER REVISION NUMBER
Similar Events a reactor scram which occurred during an instrument surveillance due to a valving error.
Although LER 85-010 describes a physical plant event rather than failure to comply with the plant's licensing bases with respect to equipment operability determination, it did present an opportunity to identify earlier the condition described in LER 2001-001, Rev.
1. The event investigation had focused on procedural compliance and not on independent verification issues.